1. Field of the Invention
This invention relates to peripheral controllers used in I/O systems for controlling data transfer operations between a main host computer and a plurality of peripheral terminal units.
This application is a continuation-in-part of U.S. Ser. No. 052,821, filed June 27, 1979 now abandoned, and entitled "Microprocessor System Operating With Normal or Slow Memories", inventors Brian K. Forbes and Robert D. Catiller.
2. Cross References to Related Applications
This application is related to the following patent applications filed as follows:
A patent application entitled "Microprocessor System Facilitating Repetition of Instructions", inventors Robert D. Catiller and Brian K. Forbes, filed June 27, 1979, U.S. Ser. No. 052,687 and now U.S. Pat. No. 4,292,667.
A patent application entitled "Microprocessor System with Source Address Selection", inventors Robert D. Catiller and Brian K. Forbes, filed June 27, 1979, U.S. Ser. No. 052,477 and now U.S. Pat. No. 4,290,106.
A patent application entitled "Microprocessor Having Word and Byte Handling", inventors Robert D. Catiller and Brian K. Forbes, filed June 27, 1979, U.S. Ser. No. 052,478 and now U.S. Pat. No. 4,301,505.
A patent application entitled "Digital System for Data Transfer Using Universal Input-Output Microprocessor", inventors Robert D. Catiller and Brian K. Forbes, filed June 27, 1979, U.S. Ser. No. 052,336 now U.S. Pat. No. 4,293,909.
A patent application entitled "Microprocessor System with Specialized Instruction Format", inventors Brian K, Forbes and Robert D. Catiller, filed June 27, 1979, U.S. Ser. No. 052,350 now U.S. Pat. No. 4,291,372.
Certain prior patents of the assignee of this invention form a background and understanding of the type of I/O systems used herein and these patents, listed below, are included herein by reference.
U.S. Pat. No. 4,162,520 to Darwen J. Cook and Donald Millers II entitled "Intelligent Input/Output Interface Control Unit for Input-Output Subsystem". This patent described a unit called a Data Link Processor for handling I/O data transfers.
U.S. Pat. No. 4,189,769 to Darwen J. Cook and Donald Millers II entitled "Input-Output Subsystem for Digital Data Processing System". This patent described peripheral-controllers organized into base module units to form an I/O subsystem.
U.S. Pat. No. 4,280,193 to Kenneth W. Baun and Jimmy G. Saunders entitled "Data Link Processor for Magnetic Tape Data Transfer System". This patent described a peripheral-controller made of a standardized card, called Common Front End, and a particularized card called the PDB or Peripheral-Dependent Board.